Rheological behaviour elastomer

Knowledge of rheological behaviour of elastomers is of considerable importance in predicting and understanding their processing characteristics. The... 

Measurement of processability and rheological behaviour of raw (unvulcanised) elastomers at variable shear rates and temperatures (viscosity and elasticity) THS Rheometer BS EN ISO 9001 [39] Negretti Automation ... 

In recent years, it has been possible to demonstrate the correlation between the molecular weight distribution (M WD) of a polymer and its rheological behaviour. It is obviously necessary, therefore, to keep this parameter under control during the polymerisation process. By its very nature, the catalyst system used to manufacture ethylene-propylene elastomers will produce polymers with a fairly narrow MWD which can, however, be varied between certain limits. In commercial polymers, the M /M ratio, which is a good indication of the MWD, generally varies between 3 and 5. 

Veenstra H., Hoogvfiet R.M., Norder B., De B., and Abe P. Microphase separation and rheology of a semicrystalUne poly(ether-ester) multiblock copolymer, J. Polym. Sci. B. Polym Phys., 36, 1795, 1998. Garbrieelse W., SoUman M., and Dijkstra K., Microstmcture and phase behaviour of block copolyfether ester) thermoplastic elastomers. Macromolecules, 34, 1685, 2001. 

Rheological properties and mixing behaviour of natural rubber In order to study the effect of rheological properties of elastomers on their behaviour in the internal mixer, some experiments were performed using various natural rubber kindly supplied by MRPRA (x). Natural rubber rheology has not been deeply studied despite the commercial importance of this material, and only a few recent papers deal with the mixing of natural rubber (19, 20, 21) and rheological comparison between natural and synthetic cis-1,4 polyisoprenes (22). 

The rheological approach to rubber processing allows a better understanding of the flow behaviour of elastomers to be achieved. Obviously the picture is far from being complete and due to their complexity, rubber compounds are exhibiting phenomena not yet completely understood. 

Clays compatibilized and evenly dispersed in the rubber matrix tend to build networks at low concentration. Rheological measurements allow us to observe the occurrence of the filler networking phenomenon at low filler content (even 4 phr) in rubber matrices such as IR, ENR, SBR, EPR. At zero shear, the viscosity of RCN is thus higher than the one of the neat elastomer. However, OC reduces the steady shear viscosity of RCN, with pronounced shear-thinning behaviour, increasing with the clay content, a higher extent of extrudate, a... 

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